Automatic brake-applying mechanism for trailers



April 13 i926. 1,580,812

J. H. CLARK AUTOMATIC BRAKE APPLYING MECHNISM FORTRAILERS Filed Nov. 17,1922 2 sheets-sheet 1 /j 1 Snom/U60@ LZ2/M5 azz /z April 13- 1926. v1,580,812

J. H. CLARK v yAUTOMATIC BRAKE APPLYING MECHANISM FOR TRAILERS FiledNov. 1'7, 1922 2 sheets-sheet 2 vwamtoz Patented Apr. 13, 1,926.

UNITED STATES JAMES CLARK, 0F DETROIT,y MICHIGAN.

AUTOMATIC BRAKE-APPLYING MECHAN ISM FOR TRAILERS.

Application illed November-'17, 1922. Serial, No. A601,559.

To all whom it may concern:

Be it known that I, JAMES HARRY CLARK, a citizen of the UnitedStates ofAmerica, and a resident of Detroit, in the county of Wayne and State ofMichigan, have invented certain new and useful Improvements in andRelating to Automatic Brake-Applying Mechanism for Trailers, of whichthe following is a full, clear, concise, and exact description, such aswill enable others skilled in the art to which said invention relates tomake and use the same, reference being made therein to` the accompanyingdrawings, which form a part of this specification.

My invention relates to trailers designed to be drawn by tractors,trucks, or like motor driven vehicles, and particularly to brakeapplying mechanism for the trailer designed to operate automatically toapply brakes to the trailer wheels if and when the trailer runs forwardrelative to the hauling vehicle, as when descending an incline; and theprincipal 'object of my `invention is to provide improved automaticallyoperating brake applying mechanism of the type or class, and for thepurpose above stated.

A further object of my invention is to` provide improved brake mechanismof the kind referred to and wherein means are provided for controllingthe device manually; so that the brakes may be applied to the trailerwheels when it is unconnected' with a hauling agency, and so alS-thatthebrakes may be prevented from "operatin if and when it is required toback :the trai er by the tractor or other hauling agency.

lVith the above and other objects -of invention in view my inventionconsists in the improved automatic brake mechanism illustrated in theaccompanying drawings and hereinafter described and claimed; and in suchvariations and modifications thereof, within the scope of the concludingclaims. as will be obvious to those skilled in the art to which myinvention relates.

In the drawings accompanying and forming a part of this specificationand wherein the preferredI form of my invention is illustrated, andwherein the same parts and y`lfeatures are designated by the samereference numerals in the several views:

Figure 1 is a view showingrv in side elevation a trailer equipped withmy improved brake mechanism, and drawn by a tractor.

Figure 2 is a fragmentary view showing the principal parts of my.improved brake mechanism in section for the most part, upon a verticalcentral and longitudinally extending plane.

Figure 3 is a view similar toFig'ure 2 but showing the parts in otherpositions, and showing also the brake mechanism per se associated withone of the trailer wheels.

Figure 4' is a fragmentaryv view contracted in several respects showingmy improved brake mechanism in its entirety, and in 1an.

Figure 5 is a fragmentary plan view s owing certain parts of my im rovedbrake mechanism as operated by han to apply the brakes. v

Figure 6 is a view showing a section upon a vertical plane indicated bythe line 6, 6 'Figure 4, looking toward the left.

Figure 7 is a view 'showing a section upon a vertical plane indicated bythe line 7, 7, Figure 4. -Y

Figures 8 and 9 are views showing a certain cam of my im roved brakemechanism separate and apartl rom other partsthereof.

Referring now to the drawings, the draw bar through which the -trai1er A-is drawn from the tractor --B--, both of which may be-of any desiredtype and construction, is made up of two lspaced bars 10, 10 preferablychannel shaped in cross-section; the rear ends of saidy members beingconnected with the forward vaxle 11 of the trailer from which theyextend substantially parallel for a portion of their length, and I arethen inclined toward one another and through a spring 16 the'front endof whichabuts against the front' spacer block, and the rear end ofvwhich abuts against a sleeve 17 slidable ythrough an opening in the rearspacer block; said sleeve having stop flanges or collars at itsA twoends to llimit its movei ment in both directions. The rear end of the.pull rod is provided with a nut 18 from which 1t follows that tractiveforce exerted along the pxull rod is communicated to the draw bar trough the sleeve 17, the spring 16 and the forward spacer block; whileat the same-time the sai pull rod may move relatively backward andfreely through the spacer blocks 1f and when the trailer runs forwardtoward the tractor; as thereis considerable space between the front faceof the front spacerblock and the eye 15.

Extending between the inclined portions of the draw bars 10, 10 andsecured in place by bolts 19 is a supporting plate 20; and supportedbeneath and from thi: plate as by means of bolts 21 is av housing havinga rear uide member shown as in the form of a cy 'nder portion 22, afront guide 23,

and a chamber 24 between said parts withinv which a controlling cam tobe hereinafter I described operates; said cam being supportedbgetrunnions rotatably supported in a lower aring 25 carried by thehousing, and in an upper bearing 26 provided in the plate '20; said cambeing movable about a vertical axis and through an angle of 180degreesas will hereinafter appear. A lower tie plate 27 extends betweenthe inclined portions of the draft members beneath the housing aforesaidand is secured in place by the same bolts 19 which fasten the upperplate 20 in place; said bolts extending through both plates and throughthe upper and lower webs of the channel shaped draw bars as will beappreciated. l

Movable longitudinally within the cylinder 22 is a hollow plunger 28closed at its forward end, and having a removable'head 29 at its rearend, and within which a spring 30 acting under compression is located.The forward end of this spring acts against an abutment 31 upon the rearend of a longitudinally movable strut bar 32 .which extends through abearing 33 in the front head of the plunger 28, through the chamber 24and bearing 23 and to a position close to the rear end of the pull rod14 when said rod is held in its rearmost position by the spring -16acting through the sleeve 17 and nuts 18; movement o said sleeve in bothdirections Vbeing limited by flanges at the ends thereof which. engagethe front andi rear sides of the rearmost spacing block 13as will beunderstood from Figure 4 of the drawings. The rear end of said spring 30acts against an abutment 34 upon the forward end of al brake applyingrod 35 extending through the head 29 o 28 and throug which, the samethen acting as a strut under compression, brakes are ap lied to thefront wheels of the trailer if an when, as when goin down hill, thetrailer starts to run forwa under the action of gravity.y

the plunger l the front and the 'rear wheels; as my 1n,

vention contemplates nothing further by way of construction andarrangement or other details of brakemechanism than that suitable brakemechanism for the trailer shall be operated by the said push rod' if andwhen the trailer runs forward upon the tractor as hereinbeforeexplained.

.In the suitable brake mechanism illustrated, however, the rear end ofthe brake applying rod 35 pushes against the lower end of a lever 36which is pivotally supported from a bracket 37 secured to the front axle11and the upper end of which is connected with the forward end of atension link 38 slidable through a hole in an upwardly extending arm 39of the bracket 37; and the rear end of which link is. connected at themiddle point of an equalizing bar 40 the ends of whlch extend into oneo-r another.I

of pairs of holes arranged in sectors 41, 41, to thereby rovide forproper adjustment as thenbrake s oes become worn; which'sectors' -arefast upon the inner ends of oscillating drums, anda s ring 49 surroundsthe link 38 and acts un er compression between the arm 39 and theequalizing bar 40 to hold the brake a plying mechanism in the positionin which it is shown in Figures 2. and 4;` with the plunger 28 pressedforward and into the cylinder 22, and the forward end of the strut orcompression bar or rod 32 close to the rear end of the pull rod 14.

When the tractor 1s pulling the trailer Athrough the pull rod 14 anddraw bars 1Q, 10 the brake applying mechanism is in the normal positionvin which lit is shown in old the brake shoes normally out of vcontactwith the interiors of the brake end of which now forms'an' abutment,and,

' designates la .cam Vmember located within. the' as the trailercontinues to move toward the tractor, the strut bar 32 will remainstationary relatively to the forwardl moving trailer; with the resultthat the sprin 30 is compressed by force acting throng the abutment 31,the plunger 28 and abutment 34 are moved rearward together as shown in`Figure 3, and force is applied to the brake mechanism through the pushrod 35 and brake mechanism above explained to force the brake shoes intocontact with the brake drums. During this action it is obvious thatrearward movement of the strut member 32 1n excess of that refgiired toapply the brakes will be permitted y and w1ll act' to compress-thespring 30; said spring acting both to prevent injury to the brakemechanism by excessivevrearward movement of `the st-rut 32, or excessiveforward movement of the trailer, as well also as to secure theapplication of the brakes through a yielding spring pressure. 'p 7Obviously rearward movement of the plunger 28 and of the brake applyingrod 35, by whatever agency brou ht about, will' result in theapplication of t e brakes' and obviously also 1f rearwardl movement ofplunger and rod is prevented then the brakes cannot be applied, eventhoughlthe ull rod 14 and strut 32 be moved rearwar asin said secondmentioned case rearward movement of said member 32falthough` it maycompress the sprin 30 will not bring about the application o the brakes.Inord er, therefore, to provide for the manual applicationl of thebrakes when the tractor vis not hauling the trailer, as for the purposeof holding the latter upon an incline;vand in 'order to prevent theapplication of the brakes when it is required to back the-trailer fromthe tractor,'inl which case the pull rod 14 and the strut bar 3 2willobviouslybe moved rearward, I providey the following elements andfeatures of my'ilproved brake applying mechanism. p

The plunger 28 is provided witha'forwardly extending arm having u .perand lower rollers 51, 51 at its front en' and 52l ported within thebearings25, 26 aforesai this cam member being provided with elonl gatedrecesses 55, 55r i'nwhich the,rollers A51, 51 may move freely\when theparts are in the positions shown in Figures 2 and v4;

the plunger-being thus free to move so that said I 'by engagement withthe bottom wallso recesses, and the brakes cannot be applied;

the brakes will be applied upon forwardI movement of the trailer ashereinbefore explained.

Fixedly secured upon the upper end of the upper trunnion 54 is an arm56; and 57 70 designates an operating handle and latch member pivotallyconnected at 58 within a recess in the end of the arm, and having a lugportionv 59 which, when said member is swungt over to the left,I Figure2, and

onto the arm 56, `enters in between spaced lugs 60 upon' the plate 20and holds the cam memberlocked in the position in which it is showny ,inFigures 2 and 4. Figurev 2 shows the cam as unlocked and, uponswinging'the handle 57 vtoward the observer, referring v,to said ligure,or downward, referring to Figure 4, the. cam 52 will be mowlfjed intothe position in which it is shown 1n 1 locke by turning the latch overand onto the top of the arm 56 to bring the lug 59 between other lugs 61upon the plate 20. During the movement ofthe cam above referred to theforward ends of the-recesses 9 55 will enga e the rollers 51 and forcethe plunger 28 ackward and into thev position shown in Figure 5, whichmovement will be communicated to the rod 35 -through the spring 30 thusapplying the'brakesqthe 95 operation above outlined being brought aboutby4 manual operation of the cam member through the handle 57 if and when-thl 4 brakes are tobe applied -lb hand, as w be understood.A j f V- Ifinstead ,of vswinging the handle ,and arm 56 toward the observer, Figure2,'and downward, Figure 4, the arm and handle bemoved manually in areverse direction the cam member will be swung into a posi- 10e tionsuch that the central portions yof Athe recesses 55, which are obviouslysolid walls,

will lie to the Yrear of the rollers 51; in which position the partsmayv be locked by swinging the lug` 59 invbetween` a third. pair 11u oflugs 62` upon the cover plate 20.- When' the parts are in this,4position the plunger 28 cannotbe moved rearwardby the'bar 32. becausethe rollers .51 thereof are stopped this being the position into whichthe parts are -moved if and when it is required to back' the trailerfrom thetractor by force' communicated to the trailer through the drawbar'connectin'g the two.

Having thus described and explained my' invention I.claim and desire tosecure by Letters Patent:

1. In e deviee ef `die ense deeeribed edd 12e in combination with atrailer having a draw bar through which the'same may be'drawn. brakeapplying mechanism carried by lsaid draw bar; means carried by said drawbar and acting upon forward movement ofZ the '1W re 5; in which positionit may be 35 the -116 trailer relativek to a hauling agency therefor foroperating said brake applying mechanism; brake mechanism associated withcertain of the wheels of the trailer and ally operable adapted to beapplied thereto automatically by said brake .applyin mechanism uponforward movement of the trailer as aforesaid; and a single manuallyoperable member carried by said draw bar and adapted to o rate saidbrake applying mechanism to t ereby'apply said brake mechanism to saidwheels independently of relative movement the trailer and the haulingagency when in one position, and to preventsald brake applying mechanismfrom applying said brake mechanism to said wheels upon relative movementbetween the trailer and the hauling agency when in another position. y

2. In a device of the class described and in combination with a trailerhaving a draw bar through which the same may be drawn, brake mechanismassociated with the front wheels vof thev trailer and adapted to beapplied thereto automatically upon forward movement of the trailerrelative to a hauling agency; brake applying mechanism carried by saiddraw bar and including a spring through which force is communicated tosaid brake mechanism to operate the same upon forward movement of thetrailer as aforesaid; and a manually operable member carried by saiddraw bar and adapted to operate said brake a plyingmechanism or toprevent the operation thereof according to the position into 'which saidmanumember is moved.

3. In a device of the class described and in combination with a trailerhaving a draw bar through which the same may be drawn, brake mechanismassociated with the front wheels of the trailer and adaptedgto beapplied thereto automatically upon forward movement of the trailerrelative to a hauling agency; brake applying mechanlsmcarried by saiddraw bar and including a sprlng through which force is communicated tosaid brake mechanism to operate the same u on forward movement ofthe-trailer as a oresaid; and a manuall operable rotatable cam membercarried by said draw bar and adapted when in one position to permit theoperation of said brake applying mechanism as aforesaid and when in aniother position to prevent the operatlonfjf said mechanism, and tooperate saidgmecla'- nism manually when moved lnto afrthird position.

4.- In a device of the class described an in combination with a trailerhaving a draw bar, brake mechanism associated with said trailer andadapted to be'applied to certain y of the Wheels thereof automaticallyupon forward movement of the tritil'erl relative to a hauling agency;and brake applying mechanism comprising a guide member carried by saiddraw bar, a plunger movable relative to said guide member, a rearwardlyextending brake mechanism operating rod extending through a hole in saidplunger and having an abutment at its forward end, a forwardly extendingstrut bar extending through a hole in said plunger and having anabutment at its rear end, a spring associated with said plunger andacting to force said abutments apart, and a reciprocating push rod atthe front end of said draw bar and the rear end of which is adapted toengage the front end of said strutv bar and force it rearward uponforward movement of the trailer relative to a hauling agency.

t 5. In a device of the class described and 1n combination with atrailer having a draw 1 bar, brake mechanism associated with saidtrailer and adapted to be applied to certain of the wheels thereofautomatically upon forward movement of the trailer relative to a haulingagency; brake applying mechanism comprising a guide member carried bysaid draw bar, a plunger movable relative to said guide member, arearwardly extending brake mechanism operating rod extending through ahole in said plunger and havlng an abutment at its forward end, aforwardly extending' strut bar extending through a hole in said plungerand having an abutment at its rear end, .a spring arranged between andacting to force said abutments apart, and a reciprocating push rod atthe front end of said draw bar and the rear end of which is adapted toengage the front end of said strut bar and force it rearward uponforward movement of the trailer relative to a hauling agency; and amanually operable member carried by said Adraw bar and adapted to forcesaid plunger rearward when moved in one direction, and to preventrearward movement of said plunger when moved in another direction.

' 6. In a device of the class described and in combination with the drawbar of a trailer, a plate carried by said draw bar; a housing carried bysaid late and having a rearwardly located gui e cylinder and a' anabutment within said plunger and ex- 4v. tendlngrearwardly therefrom; astrut bar having an abutment withinsaid plunger and extendinjgffforwardly therefrom and lirough saidt'strut bar guide; a spring atedwithin said plunger and acting to ce said abutments apart and againststops at the ends of said plunger; and a reclprocating push rod at theend of saiddraw bar and the rear end-of which is adapted to engage thefront end of said -strut bar and force it rearward.

7, In a deviceof the',4 class described and in combination with the drawbar of a trailer,

a plate'carried by said draw bar; a housing carried by said late andhaving a rearwardly located gui e cylinder, a forwardly arranged strutbar guide, and a chamber lo-y cated between said guide cylinder andstrut bar guide; a reciprocating plunger operating within said guidecylinder; a'brake applying rod having an abutment within said plungerand extending rearwardly therefrom; a strut bar having anabutment withinsaid plunger and extending forwardly therefrom and through said strutbar guide; a spring located within said plunger and acting to forcesaidabutments apart and against stops at the ends of said plunger; areciprocating push rod at the front end of said draw bar and the rearvend of which is adapted to engage the front end of said strut bar andforce it rearward; an arm extending forward from said plunger and intosaid chamber, and having upper and lower stops spaced apart from oneanother; a

y rotatable cam'memb'er having trunnions supported in upper and lowerbearings -provided in said plate and in said housing and having recesseswithin which said stops may move whensaid member is in one position,said recesses being of such form that said plunger will be forcedArearward when said cam member is moved into another position andwill beprevented from moving rear- `ward when said cam member is moved into a'third position; and manually operable forloclring it in the threepositions aforemeans for moving said cam member into and said. v t

8. In a device of the class described and in combination with a .drawbar comprising channel shaped members arranged with their' open sidesfacing one another and having parallel rear portions, inclinedintermediate portions, and parallel front ends whereby a hollow housingis provided at said front ends; a reciprocating push bar arrangedwithinsaid hollow housing" and through which the draw bar may be secured to ahauling agenc a plate secured in place upon the upper si es of saidchannel members and at the inclined portions thereof; a housing securedto the under side of said plate land located between the inclinedportions of said channel members, said housing having a rearwardlylocated guide cylinder, a forwardly arranged strut bar guide, and achamber located between said guide cylinder andsaid strut bar guide; ahollow reciprocating plunger operatlng within said guide cylinder andhaving a head at both` ends thereof, and an arm extending from its fronthead into the chamber aforesaid; a brake applying rod having 1anabutment within said plunger, and which rod extends rearwardly through ahole in the rear head i the free end of the arm aforesaid and prev ventsuch movement, and when moved into a third position to force said'plunger rearward through said stops and said arm.

ln testimony whereof I have signed this specification this first day ofNovember, 1922.

JAMES HARRY CLARK.

